How Blood Works

It's red, it flows through your veins, the sight of it makes some people feel faint... but how exactly does blood work?

This short video crams a lot of science into an incredibly detailed 5 minutes, which careers through everything from EPO doping to the complexities of your immune system, as well as, umm, how to get it out of your clothes. It's super interesting stuff. [The Medicine Journal via Today I Found Out]